The current Emergency Services Enhanced 9-1-1 (E911) infrastructure in North America is based on a distribution of Primary Public Safety Answering Points (P-PSAPs, hereinafter referred to solely as PSAPs) accessible from the Public Switched Telephone Network (PSTN) via a special group of telephone lines dedicated solely to emergency use. The same applies to other emergency codes used in other parts of the world, e.g., E112 in continental Europe, E999 in England, etc.
In the current infrastructure, each individual telephone number is assigned a corresponding PSAP that is nearest to the physical location of the user of that telephone number. The physical location of the user is assessed on the basis of the area code and local exchange of the telephone number. When a user places an emergency call, the calling party's telephone number is transmitted with the call, and on the basis of the originating telephone number, the emergency call will be routed to the designated PSAP along one of the dedicated emergency lines. Upon receipt at the PSAP, the call is answered by a trained responder. By virtue of an automatic location identification (ALI) database which maps each telephone number to an address, the responder is able to obtain the physical location of the calling party and dispatch a police officer, firefighter or ambulance as necessary.
With the advent of the Internet, society has witnessed the expansion of a global packet-switched network into an ever increasing number of homes and businesses. This has put ever increasing numbers of users into contact with one another, usually at little cost for unlimited use. Meanwhile, advances have been made in delivering voice communication over packet networks, driven primarily by the cost advantage of placing long-distance calls over the Internet as opposed to the leased lines of the world's telcos. Technology dealing with the delivery of real-time voice calls over a packet-switched network is generally known as voice-over-packet or voice-over-Internet-Protocol (voice-over-IP), and often simply referred to as “VoIP”.
From a purely technological standpoint, the successful deployment of VoIP has several challenges, typically related to latency and congestion. Still, despite these and other technical drawbacks, many consumers have opted to subscribe to VoIP services, motivated by significant cost savings in the area of long-distance calling. This has led to a trend, whereby some residential and business consumers have actually chosen to abandon their “basic” PSTN connection in favour of a VoIP connection, not only to satisfy their long distance requirements but also to conduct local, day-to-day telephony. One area where this shift to all-VoIP paradigm can be problematic for consumers (and VoIP service providers) is in the delivery of emergency services.
Specifically, the call delivery technology is fundamentally different for VoIP, and as a result, the dialing of 9-1-1 during a VoIP connection does not work today in the same way as for a basic PSTN connection. For example, VoIP users can select their own telephone numbers, which may comprise an “area code” and a “local exchange” that are unrelated to the physical location from which calls will be placed. If the VoIP user dials 9-1-1, the call may be directed to a PSAP located in a different part of the country, significantly reducing the value of the emergency services being provided.
Recognizing these defects, some VoIP service providers have enhanced their offerings in the area of emergency services. For example, there are consumer VoIP solutions which allow the transfer of a 9-1-1 call from the VoIP network to the nearest PSAP in accordance with level i1 of the service levels proposed by the National Emergency Number Association (NENA) and the Voice over the Net (VON) coalition.
However, in accordance with this and other i1-compliant solutions, emergency calls are not delivered via the dedicated emergency lines and trunks described above, but instead arrive at the nearest PSAP via the PSAP's ordinary, i.e., administrative, lines. Since many PSAPs are unprepared to handle calls over ordinary telephone lines, this creates a variety of problems, ranging from the low priority typically given to administrative calls, to the possibility of having an emergency call answered by improperly trained staff such as a receptionist or, worse still, by an auto-attendant during off-normal hours.
Against this background, it is clear that further improvements are needed in the delivery of emergency services to persons dialing 9-1-1 from a VoIP-enabled telephone or device.